The invention relates generally to a method and arrangement for melting charges.
A method for the continuous melting of scrap is known from the German Pat. No. 1,800,610. Scrap is charged into a vertically arranged melting chamber of substantially constant cross-section and forms a column therein. The column is melted from below with a flame which extends across the major part of the cross-section of the column and the flame is positioned at such a height above the bottom of the chamber that the molten material wich flows off is able to form a thermal barrier for the fire-resistant lining of the chamber. Melting with the high-temperature burners occurs in countercurrent fashion in that the scrap moves downwardly in the chamber while the combustion gases flow upwardly therein. The flame used for the melting operation is centrally positioned and is of plate-shaped configuration. This flame is generated by means of a burner lance which is located on the axis of the melting chamber and which extends into the latter either through the column of scrap or through the bottom of the chamber.
A plate-shaped flame which is generated by a centrally positioned burner lance, however, possesses the disadvantage that its diameter cannot be increased as desired so that, when the melting chamber is of large cross-section, it is not possible for the column of charge to be impinged by the flame over the major part of its cross-section. In this connection, it may be seen that large cross-sections for the melting chamber are of importance for increasing the throughput capacity. Furthermore, melting chambers of large cross-section make is possible the charge bulky types of scrap which do not require much preparation prior to being charged since the size of the charging opening of the melting chamber may then be increased correspondingly.
Also, in the above-described method, the molten material has a temperature which is only slightly higher than its liquidus temperature. This is disadvantageous when the molten material must be transported from the melting chamber to a converter, a Siemens-Martin oven or the like. Moreover, this may lead to blockage of the outlet opening of the melting chamber by molten material which has solidified, particularly when the molten material is to be further processed in a discontinuous operation so that the melting procedure must be interrupted.